Agricultural crops and ornamental plants are subject to attack by many kinds of fungi, both airborne and soilborne, with serious damage thereby resulting. A great amount of research has been conducted to find methods of combatting such fungi.
In the prior art, Sperber et al., U.S. Pat. No. 2,727,895 (Dec. 20, 1955), teach that certain 4-substituted pyridines, and the piperidines produced therefrom by hydrogenation of the pyridine ring, are useful primarily as anticonvulsants, and secondarily, as antibacterials and antifungals, when administered in a variety of the usual pharmaceutical forms, such as tablets, elixirs, solutions and capsules. Thus, the Sperber et al. compounds are directed toward use in animals or mammals. The claimed Sperber et al. compounds are .alpha.-phenyl-.alpha.-lower-alkyl-4-pyridylmethanes which thus differ significantly from the .alpha.,.alpha.-dialkyl-3-pyridine-methanols of the instant application. The Sperber et al. compounds showed minimal antifungal activity when compared with the dialkyl 3-pyridinemethanol compounds of the present application in tests against airborne and soil-borne fungi.
Another prior art reference is Hoffmann et al., U.S. Pat. No. 3,153,046 (October 13, 1964), which teaches dialkylpiperidylmethanols as having fungicidal, and especially antibacterial, properties useful against Microsporum audouini, Trichophyton interdigitalis, and Staphylococcus aureus, and against tubercle bacilli. Hoffmann et al. teach that their compounds can be used as disinfectants, preservatives, or as medicaments for the treatment of bacterial infections, and thus the compounds are implicitly directed to use in humans or animals. Such piperidyl compounds, which are produced by hydrogenating the intermediate pyridine compounds, for which pyridine compounds no activity is taught, have shown minimal activity in tests against plant pathogenic fungi.
Duerr et al., U.S. Pat. No. 3,203,855 (Aug. 31, 1965), teach a method for combatting phytopathogenic organisms, i.e., fungi or bacteria, using the compound 2-(2,2,2-trichloro-1-hydroxyethylamino)pyridine, which compound differs significantly from those described in the instant application.
Also in the prior art is Van Heyningen, U.S. Pat. No. 3,396,224 (Aug. 6, 1968), which teaches that substituted 3-pyridylmethane derivatives are active against phytopathogenic fungi. Optimum fungicidal activity was disclosed by Van Heyningen for his compounds only when both substituents were aryl. Thus, compounds disclosed by Van Heyningen showed optimum activity against airborne fungi and little or no activity against soil-borne fungi. This is in contrast to the instant dialkyl 3-pyridinemethanol compounds which most unexpectedly show their optimum activity against soil-borne fungi.
It is believed that a unique method of controlling fungi using .alpha.,.alpha.-dialkyl-substituted 3-pyridinemethanols has been found.